Adhesion promotion to difficult substrates for hot melt adhesives

Patent metadata

Field	Value
Publication number	US-9534155-B2
Application number	US-201514626472-A
Country	US
Kind code	B2
Filing date	Feb 19, 2015
Priority date	Mar 7, 2014
Publication date	Jan 3, 2017
Grant date	Jan 3, 2017

Abstract

Hot melt adhesive compositions which have enhanced adhesion to difficult substrates, particularly at refrigerator/freezer temperatures or at elevated temperatures. The inventive compositions require a base polymer comprising an ethylene vinyl acetate-containing polymer; a tackifier; an adhesion promoting additive comprising at least one semi-crystalline polymer having a weight average molecular weight of about 30,000 daltons or less; and optional wax; and an optional antioxidant. It has been found that the adhesion promoting additive of this invention enhances the adhesion properties of a hot melt adhesive composition having ethylene vinyl acetate-containing polymer, particularly at elevated temperatures or at low refrigerator and freezer temperatures where other conventional adhesives have been unsuccessful.

First claim

What is claimed is:

1. An adhesive composition which comprises:
a) a base polymer comprising an ethylene vinyl acetate-containing polymer;
b) a tackifier;
c) an adhesion promoting additive comprising at least one semi-crystalline polymer having a weight average molecular weight of about 30,000 daltons or less;
d) an antioxidant; and
e) an optional wax.

2. The composition of claim 1 wherein the adhesion promoting additive comprises at least one propylene containing polymer, maleated propylene containing polymer, maleated ethylene containing polymer, or combinations thereof.

3. The composition of claim 1 wherein the adhesion promoting additive comprises a maleated polymer having a SAP number of equal to or greater than 20.

4. The composition of claim 1 wherein the adhesion promoting additive comprises a maleated polymer having a SAP number of equal to or greater than 50.

5. The composition of claim 1 wherein the adhesion promoting additive is present in an amount of from about 1 percent to about 30 percent by weight of the adhesive composition.

6. The composition of claim 1 wherein the base polymer has a melt index of from about 5 to about 3000.

7. The composition of claim 1 wherein the ethylene vinyl acetate-containing polymer is present in the adhesive compound in an amount ranging from about 30 wt. % to about 60 wt. %, based on the total weight of the adhesive.

8. The composition of claim 1 wherein the ethylene vinyl acetate-containing polymer comprises between about 15 wt. % and about 85 wt. % of ethylene monomer.

9. The composition of claim 1 wherein the antioxidant comprises at least one antioxidant selected from the group consisting of sterically hindered phenols, multifunctional phenols, sulfur-contained phenols, phosphorous-containing phenols, and combinations thereof.

10. The composition of claim 1 wherein the antioxidant is present in an amount greater than or equal to 0.2 wt. %, based on the weight of the adhesive.

11. A process for forming an adhesive substrate which comprises:
I) forming an adhesive composition by combining:
a) a base polymer comprising an ethylene vinyl acetate-containing polymer;
b) a tackifier;
c) an adhesion promoting additive comprising at least one semi-crystalline polymer having a weight average molecular weight of about 30,000 daltons or less;
d) an antioxidant; and
e) an optional wax;

II) heating the adhesive composition to a temperature at or above the melting point of the adhesive composition; and
III) applying the heated adhesive composition to a substrate.

12. The process of claim 11 which further comprises the subsequent step (V) of bringing the adhesive composition to a temperature below the melting point of the composition.

13. A packaging material which comprises the adhesive composition of claim 1 .

14. A adhesive composition which comprises:
a) a base polymer comprising an ethylene vinyl acetate-containing polymer;
b) a tackifier;
c) an adhesion promoting additive comprising at least one semi-crystalline polymer having a weight average molecular weight of about 30,000 daltons or less wherein the adhesion promoting additive comprises a maleated polymer having SAP number equal to or greater than 20;
d) an antioxidant; and
e) an optional wax.

15. The composition of claim 14 wherein the adhesion promoting additive comprises at least one propylene containing polymer, maleated propylene containing polymer, maleated ethylene containing polymer, or combinations thereof.

16. The composition of claim 14 wherein the adhesion promoting additive is present in an amount of from about 1 percent to about 30 percent by weight of the adhesive composition.

17. The composition of claim 14 wherein the base polymer has a melt index of from about 5 to about 3000.

18. The composition of claim 14 wherein the ethylene vinyl acetate-containing polymer is present in the adhesive compound in an amount ranging from about 30 wt. % to about 60 wt. %, based on the total weight of the adhesive.

19. The composition of claim 14 wherein the ethylene vinyl acetate-containing polymer comprises between about 15 wt. % and about 85 wt. % of ethylene monomer.

20. The composition of claim 14 wherein the antioxidant comprises at least one antioxidant selected from the group consisting of sterically hindered phenols, multifunctional phenols, sulfur-contained phenols, phosphorous-containing phenols, and combinations thereof.

21. The composition of claim 18 wherein the antioxidant is present in an amount equal to or greater than 0.2 wt. %, based on the weight of the adhesive.

22. The composition of claim 14 wherein the wax comprises the substantial absence of a Fischer-Tropsch wax.

23. A packaging material which comprises the adhesive composition of claim 14 .

Assignees

• Honeywell Int Inc

Inventors

• Knobloch Arthur
• Jablon Michael
• Hacker Scott
• Rotz Steve

Classifications

• C09J123/0853 Primary

  Vinylacetate · CPC title

• C08K5/005 Primary

  Stabilisers against oxidation, heat, light, ozone · CPC title

• C08K3/014

  Stabilisers against oxidation, heat, light or ozone · CPC title

• C09J131/04 Primary

  Homopolymers or copolymers of vinyl acetate · CPC title

• C09J11/06

  organic · CPC title